Stem cell method keeps embryos, debate alive

New stem cell method keeps embryos and debate aliveBreakthrough lauded by many as a step toward ending impasse

Published 5:30 am, Thursday, August 24, 2006

A California biotechnology company says it has developed a way of extracting stem cells from human embryos without destroying the embryo, a potential solution to the political and ethical impasse holding back the cutting-edge science.

In a report published online Wednesday in the journal Nature, the company describes how it used single cells from 2- to 3-day-old embryos to produce stem cell lines. The process leaves the embryos intact and usually able to survive.

"There is no rational reason left to oppose this research," said Dr. Robert Lanza, vice president of Advanced Cell Technology and leader of the study. "Any excuses get more and more obscure."

A spokesman for President Bush said the new method doesn't resolve ethical concerns about the use of human embryos for research, but called it "encouraging" to see scientists "make serious efforts" to move away from research involving their destruction.

Last month, Bush vetoed an expansion of federal funding for embryonic stem cell research, arguing the government shouldn't pay for research that involves the destruction of human life. The administration limits federally funded research to a small number of lines harvested from embryos before Bush set policy in August 2001.

Lanza said he thought the new method may persuade enough legislators to support a future stem cell bill and override a presidential veto. Senate support of last month's bill fell four votes short of being able to override Bush's veto.

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Caution voiced

Embryonic stem cell research is one of the most prominent technical scientific matters in modern political discourse. It was a major issue in the 2004 president campaign, with Democratic candidate

John Kerry
attacking Bush's position as "anti-science" and first lady
Laura Bush
accusing proponents of overstating the field's potential.

Advanced Cell Technology's new method was hailed by stem cell researchers frustrated by the controversy, but many cautioned that it was not the sort of breakthrough that will open up a new industry or sway those passionately opposed to the field.

Lanza said the method would merely be useful for expanding the pool of ethically acceptable stem cell lines available for research. He acknowledged the technique is too inefficient to be routinely used for clinical application.

Embryonic stem cells are considered the key to regenerative medicine, often touted as the future of health care. Typically retrieved from 5-day-old human embryos, they can morph into virtually every kind of tissue — versatility scientists hope one day will provide a source of replacement parts for organs involved in disorders such as diabetes and Parkinson's.

Used in fertility clinics

Lanza's team used a method already employed in fertility clinics to remove one cell from a human embryo without harming it, then grew stem cells from it. The technique is used when the embryos is 2 days old, after the fertilized egg has divided into eight cells.

In fertility clinics, one of those cells can be removed for diagnostic tests, such as Downsyndrome or cystic fibrosis. The embryo, now down to seven cells, can be implanted in the mother if no defect is found.

About 1,000 such procedures are performed each year in the United States.

In the Nature report, Advanced Cell Technology claimed it was able to produce two viable stem cell lines from the 16 embryos with which it worked. Researchers wrote that the cell lines were "genetically normal and retained their potential to form all of the cells in the human body that could potentially be used to treat a range of human diseases."

They acknowledged that more research needs to be done.

But news of the technique drew no shortage of criticism.

Impact on embryo unknown

Richard Doerflinger
, deputy director of anti-abortion activities for the U.S. Conference of Catholic Bishops, said the study "raises more ethical questions than it answers." He noted that the experiment itself was "gravely unethical" because it involved thawing and manipulating 16 embryos and then discarding them.

William Hurlbut, a Stanford University professor and a member of the President's Council on Bioethics who has proposed alternative methods for generating stem cells without destroying embryos, noted that occasionally embryos don't survive fertility clinics' diagnostic tests.

"We also don't know the effect of a cell's removal if the embryo does survive," said Hurlbut. "Embryos have a capacity for healing, but healing has an effect. We don't know if, say, the child ultimately created is endangered in later life or is different in some way. We just don't know."

Lanza said he thinks it would be ethically wrong to use the technique on embryos that weren't undergoing the diagnostic test already.

Baylor College of Medicine researcher Dr. William Brinkley said he thought the study was "a neat piece of work," but worries that if politicians ever approve it for federally funding, it will scare them away from endorsing more cutting-edge research involving the destruction of embryos.

Lines available to scientists

Embryonic stem cell research has been particularly controversial in Texas, where bills in the state Legislature have sought to criminalize the activity. Although a handful of researchers at Baylor and the
University of Texas Health Science Center
at Houston conduct research on the federally approved embryonic stem cell lines, most of the local stem cell work focuses on adult stem cells.

Lanza's research comes less than a year after he published a similar paper in Nature showing the same technique could be used to create stem cell lines without destroying mouse embryos.

He said his company would make any stem cell lines available to scientists for free.

"If there weren't such political controversy about embryonic stem cell research, this wouldn't be a great step forward," said Rick Wetsel, a stem cell researcher at UT-Houston's Laboratory for Developmental Biology. "But as far as I'm concerned, anything that might bring opponents on board and overcome this impasse is a good thing."